German Patent No. 10 2010 038 703 describes the uses of the electrical properties of a rotating electric machine for differentiating individual electric machines of a same production series from one another (“fingerprint”). It was proposed in this publication to use electrical properties, in particular the induction of electric machines, for their identification. This approach is based on the assumption that due, for example, to differences in the windings of the individual electric machines, which are also detectable in electric machines of a single production series, the corresponding inductions are different, it being possible to use these differences for differentiating the electric machines from one another. However, this method only functions (when relatively economical measuring systems are used) for devices satisfying only low to medium quality requirements and having tolerances of a similar magnitude. For production series which must satisfy higher tolerance requirements, the differences in the above-named parameters or electrical properties are very small, making it difficult or hardly possible to identify individual electric machines, in particular when relatively simple measuring devices are used. In any case, very complex and accordingly expensive measuring systems must be used for this purpose.
The present invention is intended to provide a simple identification or authentication method for rotating electric machines, which may also be used for production series having low tolerances.